<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>

<body>
    <script>
        var cities = [{ spell: "tianmen", city: "天门" }, { spell: "tianjin", city: "天津" }, { spell: "tianshui", city: "天水" }]

        var arr = []
        cities.forEach(item => {
            if (item.spell.startsWith("tian") || item.city.startsWith("天")) {
                arr.push(item.city)
            }
        })
        console.log(arr)
    </script>
</body>

</html>